Flashcards
Forces
Cards in this deck (36)
- 1ForceA push or a pull
- 2Contact ForceA force that is exerted directly on an object.
- 3When does friction occur?When 2 surfaces are pushed against each other so that their particles are in close contact.
- 4Effects of friction- Friction causes heat
- Moving objects are slowed down
- Surfaces wear - 5LubricantA substance that reduces friction between 2 moving surfaces
- 6Static frictionThe opposite frictional force that is at its maximum value and before the object starts to move
- 7Sliding frictionThe opposing frictional force that is slightly less than the static friction and the object moves at a constant speed.
- 8Newton's 3rd LawThe mutual similar forces of action and reaction between 2 bodies are equal, opposite and collinear.
- 9Nature of Force- Forces may be attractive or repulsive.
- Forces have both magnitude and direction. - 10Forces having magnitude and direction (vector)If more than 1 force is applied, the combined effect of all the forces may keep the object stationary if the forces are balanced, or move the object if unbalanced.
- 11Resultant ForceThe single force that has the combined effect if all the forces operating on a body.
- 12Hooke's LawThe extension of a spiral spring is directly proportional to the stretching force, provided that the spring is not stretched beyond its elastic limit
- 13RotationThe effect of a force when it is applied to a body which is free to move around a point.
- 14Fulcrum/PivotThe point about which rotation occurs.
- 15MomentThe product of the force and the perpendicular distance of the line of action of the force form the pivot.
- 16Moment (Formula)T = Fd (T (tau) = moment, F = force, d = perpendicular distance)
- 17Law of MomentsFor a lever in equilibrium, the sum of clockwise moments equals the sum of anticlockwise moments.
- 18A body is in equilibrium when:- The resultant force is 0.
- The sum of clockwise moments equals the sum of anticlockwise moments. - 19Centre of mass/gravityThe point at which the whole weight of the body is considered to act.
- 20Position of centre of gravity- It determines whether a body topples or not.
- A body topples when the vertical line through its centre of mass falls outside of its base and has a moment which topples the body. - 21Stability of an object is increased by:1. Lowering the centre of mass.
2. Increasing the are of the base. - 22Stable equilibrium- The object returns to its initial position.
- Centre of mass rises when displaced.
- Weight has a moment around the point of contact (hence it rolling back). - 23Unstable equilibrium- Object moves further away from its initial position when slightly displaced.
- Centre of mass falls because it has a moment about the point of contact which increases displacement. - 24Neutral equilibrium- The body remains in its new position after being displaced.
- Weight acts through the point of contact, therefore, there is no moment to increase or decrease the displacement. - 25LeverA device that can turn about a pivot.
- 26EffortThe force applied to operate the lever.
- 27LoadThe resisting force.
- 281st class lever- A lever that has the fulcrum between the effort and the load (EFL)
- E.g. Scissors, see-saw, pliers - 292nd class lever- Load is between the effort and the fulcrum (ELF).
- E.g. Wheelbarrow, nutcracker, bottle opener. - 303rd class lever_ Effort is between the load and the fulcrum.
- E.g. Elbow, sugar tongs. - 31Resultant of a number of vectorsThe single vector that will have the same effect as all the original vectors acting together.
- 32Equilibriant of a number of forces- The single force that keeps all the other forces in equilibrium.
- It's equal in magnitude but opposite direction to the resultant of the forces. - 33Triangle LawIf 3 forces are in equilibrium, they van be represented in both magnitude and direction by 3 sides of a triangle taken in order.
- 34Triangle Law
- 35Effect of force and mass on accelerationAcceleration is:
1) Directly proportional to the resultant force for a fixed mass.
2) Indirectly proportional the mass for a constant force.
- Therefore, F = ma - 36Newton's 2nd LawWhen a resultant force is applied to a body, it produces an acceleration in the direction of the force that is directly proportional to the force and inversely proportional to the mass of the object.
Information
- Description
- Cambridge IGCSE Chemistry, Biology and Physics Flashcards on Forces, created by Taylor Smith on 25/05/2015.
- Created by
- Taylor Smith
- Views
- 23
- Rating